Harvest Moons and the Seeds of Our Faith

How the fall equinox, and the science of ancient astronomy, helped shape religions.

By

Zeeya Merali

Updated Sept. 17, 2010 12:01 a.m. ET

Next Wednesday heralds the official end of summer—the autumnal equinox —when the length of day and night are equal (circa 11:09 p.m. ET). In the 21st century, this astronomical event is little more than a passing curiosity. But rewind by about three millennia to the time of the ancient Babylonians, and the autumnal equinox marked the start of the "minor new year." Not only did celestial events define sacred festivals. Conversely, religion powered the development of astronomy, the first science.

Today, science and religion are often thought to be very different, unconnected disciplines. But looking back at our ancient past, we see that the development of religion and early science have really gone hand-in-hand, shaping some of the characteristics of mainstream religion in ways we may not realize.

For instance, while the Babylonians celebrated their "main new year" in the spring, their tradition of having a minor autumnal new year has carried over into both mainstream religion and secular practice. Nick Campion, a historian of cultural astronomy at the University of Wales, notes two echoes of ancient autumn observances today. "It's a custom inherited by Jews—hence Rosh Hashanah," he told me, "while the beginning of the academic year in autumn is a secular legacy."

The Babylonians made meticulous records of celestial events. To them, as to many ancient civilizations, the sky was thought to be the writing pad of the gods, while the stars and planets were the ink used to communicate divine messages.

Through today's lens, the practices of star-gazing Babylonian priests may appear to be based mostly in superstition. Each night they searched the sky for omens sent by the great god Marduk or one of his entourage of lesser deities. Unexpected wanderings of the planets might foreshadow a poor harvest in the village, while the early risings of the moon could portend malformed births. By far the worst harbinger was a lunar eclipse, which signaled that the gods were angry with the king and called for his death.

Much early astronomy dealt with developing techniques to predict these omens, allowing crucial time for pre-emptive prayers and rituals to ward off misfortune.

Despite being tied to religious ritual (and often to gruesome sacrifice), the work of these priests marks the beginnings of science, says John Steele, a historian of ancient astronomy at Brown University. "They were making mathematical predictions based on empirical observations, which is astronomy by definition," he says.

An even more detailed understanding of celestial phenomena influenced the decline of polytheism. As more sophisticated science showed that the astronomical events were routine and could be predicted, they lost their ability to inspire fear. By the 5th century B.C., Greek philosophers were developing a view that the universe originated from one divine source.

Nick Campion adds that with the rise of the monotheistic Abrahamic religions, the need to "secularize the planets"—stripping them of divine agency—became even more pressing. Astronomy could not be written out of religion completely, in part because in people's minds the celestial patterns were so clearly tied to the changing of the seasons. So monotheistic religious leaders emphasized the importance of sacred calendars governed by predictable celestial motions.

They argued also that understanding the behavior of planets and stars was the route to revealing what Mr. Campion calls the "unfolding of God's plan." For a time, he notes, astronomy actually became a tool of power for the religious elite to wield, The better religious scholars were at predicting astronomical events, the more society was seen to be successfully harmonizing with God.

In the early Islamic empire, astronomical patterns dictated not only the calendar, but also the architecture of cities. Mr. Campion has studied the original plans for building Baghdad, which was designed to be laid out in seven concentric circles––to mimic the geocentric view of the cosmos held at the time, with earth at its center, and the sun, the moon and the five then-known planets in orbit around it.

Although those plans were partially abandoned, the ultimate framework of the city was indeed circular and its foundations were laid on a day calculated to coincide with the time that Jupiter, then thought to be the supreme power-giving planet, rose above the Eastern horizon. "Baghdad was literally a cosmopolis," says Mr. Campion.

Baghdad is one example of how an ancient society was built to celestial blueprints. To fully appreciate some of our religious practices today––and sometimes even the layout of the ground under our feet––we must look back to the earliest science and the influence of the night skies.

Ms. Merali is a science writer and documentary producer based in London.

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